I ordered the rim drive kit from Music Direct during January and finally took delivery of the kit on Monday of this week. I installed the new drive mechanism in my VPI TNT-6 turntable on Monday evening, and I have done some fairly extensive listening since then. Here is a run down on the changes in performance I am hearing in the SET audio system where I am running my TNT-6 turntable (equipped with the Super Platter):
1. PRaT - The new drive mechanism delivers a sense of energy and flow to the music that is clearly superior to the belt-drive mechanism. By comparison, the belt drive sounds somewhat slow and sluggish. (For those of you wondering whether I used the SDS to calibrate the platter speed before making this observation, I did.)
2. Bass Performance - With the new drive mechanism, the performance of the turntable is significantly improved in the bass frequencies. The bass is faster and tighter. By comparison, the bass frequencies with the belt drive mechanism tend to sound ponderous with a certain resonance or overhang that tends to muddy up the works - particularly in a full-range audio system.
In addition to the performance improvements noted above, I believe that dynamics have also improved.
Overall, I think the new drive mechanism is a very worthwhile upgrade that does a nice job of addressing some of the inherent weaknesses I have come to understand about the VPI TNT turntable in the eight years I have owned it. (My first VPI turntable was the TNT Mk3.5, which over the years was gradually upgraded and replaced, piece by piece, as it evolved into what is now the latest production model version).